JPH02282715A - Optical deflector - Google Patents

Abstract

PURPOSE:To adjust the inclination between the best image plane and a scanned surface by adjusting an optical unit so that it can rotate. CONSTITUTION:The heights of the optical unit 10 and a base 20 are adjusted by using four pins A, B1, B2, and B3. A positioning pin C used when the optical unit 10 is fitted to the base 20 is fixed on the surface of the optical unit 10 which faces the base. A pin D which is movable along a laterally long unloaded hole E in parallel to a scanning line formed on a surface to be scanned as a deflector rotates is fixed to the optical unit after its movement. Here, even if the best image plane and the surface to be scanned slant because of the working accuracy and fitting errors of optical components, the whole optical unit of this invention can be rotated in a plane of deflection around the pin C by moving the position of the pin D about the optical unit. Consequently, the surface to be scanned can be matched with the best image plane.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a light deflection device using a deflector such as a rotating polygon mirror, and in particular to a light source section and a deflector for deflecting a light beam from the light source section. The present invention relates to an optical unit having a container and a structure for mounting a base on which the optical unit is mounted.

[Prior Art] In a light deflection device for a recording device such as a laser beam, an optical unit is assembled in which optical components of a scanning system such as a single rotator mirror and an fθ lens are assembled as one unit, and the optical unit is attached thereto. For this reason, the optical deflection device is divided into two large parts: a main body (base) that serves as an optical deflection device. In such an optical deflection device, the scanning line may deviate from a predetermined position due to the processing precision and mounting precision of each optical component. For this reason, in order to adjust the position of the scanning line, conventional optical deflectors have a structure in which the optical unit can be mounted on the base by moving it up and down with screws or the like. However, the mounting of the optical unit on the base is not structured so that its position can be rotated within the deflection plane (the beam flux plane formed over time by the light beam deflected by the deflection reflection surface of the deflector). There wasn't. Therefore,
In conventional optical deflection devices, there is no means for correcting when the range where a good spot can be obtained (best image plane) and the surface to be scanned (for example, the surface of a photosensitive drum) are tilted. This is because the target laser beam spot diameter of the device is about 100 μm, and the depth to maintain this good spot diameter is about ±6 mm, so the processing accuracy and installation of each optical component are accurate. The inclination between this best image plane and the scanned surface has been kept within an allowable range.

However, in the case of a highly detailed optical deflection device in which the target laser beam spot diameter is about 40 um, the depth is as narrow as about ±0.8 mm. Therefore, in order to correct the tilt of the image plane and the scanned surface by improving the processing accuracy and mounting accuracy of the parts as with conventional devices, it is necessary to process the parts in order to obtain a good spot on the entire scanning surface. Accuracy and mounting had to be excessively precise, making processing difficult and increasing costs. Furthermore, even if the tilt could be kept within the depth range, there would not be enough depth for the entire scanning surface, so depending on environmental changes, the spot diameter could increase in a part of the scanning surface and exceed the permissible range. .

[Summary of the Invention] In order to solve the problems of the conventional device described above, the present invention provides an optical unit having a light source section and a deflector that deflects a light beam from the light source section, and a base on which the optical unit is mounted. In the optical deflection device, the optical unit is rotatably attached to a base.

In this way, when attaching the optical unit to the base, the position can be adjusted so that the optical unit rotates, making it possible to adjust the inclination between the best image plane and the scanned surface. .

[Embodiment] A first embodiment of the optical deflection device of the present invention is shown in FIGS. 1(a) to 1(C). FIG. 1(a) shows the optical unit 10.
FIG. 1(b) is a view of the optical unit 10 viewed from the bottom side (the mounting surface side of the base 20, which is the main body of the apparatus), and FIG.

The attachment of the optical components of the scanning system such as the fθ lens is shown as seen from the front side), and FIG. 1(C) is a view of the optical unit 10 as seen from the side. In the figure, A is a height reference bin, and B1B2. A screw is attached to the pin B3, and it can be moved in a direction perpendicular to the plane of the paper in FIG. 1(a).

A, Bl, B2. The heights of the optical unit 10 and the base 20 are adjusted using the four pins B3. C is a positioning pin when attaching the optical unit 10 to the base 20, and is fixed to the surface of the optical unit 10 facing the base.

A pin D is movable along a horizontally long hole E in a direction parallel to a scanning line formed on the surface to be scanned as the deflector rotates, and is fixed to the optical unit after movement. - The optical unit according to this embodiment can be attached to the base by aligning the pins C and D with the holes on the base side. Also,
1 is a light source section having a semiconductor laser and a collimator lens;
2 is a rotating polygon mirror which is a deflector, and 3.4 is an f-θ lens for scanning consisting of two single lenses.

Here, the machining accuracy and installation of optical parts may be subject to second-order errors due to errors.
Even when the best image plane and the surface to be scanned are tilted as shown in Figure 2(a), in the apparatus of this embodiment, the position of the pin D relative to the optical unit can be moved as shown in Figure 2(b). Since the entire unit can be rotated within the deflection plane around the pin C, the best image plane can be made to coincide with the scanned plane.

To adjust the inclination between the best image plane and the scanned surface, the optical unit is rotated within the deflection plane around the pin C, and after the best image plane and the scanned surface are aligned, the pin D is fixed to the optical unit. The position (height) of the scanning line can be adjusted using pins B, , B2. Do it in B3. The height of the pin D is adjusted using a standard base (a base according to the designed value). On the other hand, when mounting on the base side, the holes are fixed after adjustment using a standard optical unit (an optical unit that meets the design values). The optical unit that has been adjusted is mounted on this base so that the hole and the positioning pins C and D of the optical unit coincide with each other to form one optical deflection device. In this way, the adjustment on the optical unit side is adjusted as an individual unit based on the standard base, and the installation on the base side is different from the individual units when adjusting the device using the standard optical unit. Since they are independently adjusted as individual bases, even if a unit breaks down, it can be easily replaced.

Furthermore, in the above-mentioned embodiment, among the pins C and D, pin D, which is closer to the surface to be scanned, is a movable pin, and pin C, which is farther from the surface to be scanned, is a fixed pin. It is also possible to have a configuration in which the pin D, which is closer to the surface to be scanned, is a fixed pin, and the pin C, which is farther from the surface to be scanned, is a movable pin.

In the embodiment described above, the central axis of the fixing pin C, that is, the rotation axis of the optical unit, is configured to be within a plane that includes the optical axis of the 3.4 fθ lens and is perpendicular to the deflection plane. With such a configuration, the inclination between the best image plane and the scanned surface can be adjusted while maintaining the symmetry of the scanning line.

In the above embodiment, the optical unit has a fixed pin and a movable pin, and a hole is provided for mounting on the base, but conversely, the optical unit has a hole for mounting and is fixed on the base. A configuration in which a pin and a movable pin are provided is also possible.

A second embodiment of the optical deflection device of the present invention is shown in FIGS. 3(a) and 3(b). Figure 3(a) shows the optical unit 1O with the lower side (
The attachment of the base 20, which is the main body of the apparatus, is a view seen from the front side), and FIG. 3(b) is a diagram showing the state in which the optical unit 10 is attached to the base 20. In the same figure, F,...
F is two positioning pins fixed to the optical unit, and pin G is located in the hole H in the same way as pin D in the first embodiment.
can be moved along. There is a guide rail (2) and a mounting hole (J) on the base, and the guide rail (I) has a curvature centered on the center 0 of the surface to be scanned.

In a state where the pin G on the unit side is not fixed, the unit is movable while the pins F, , F2 are in contact with the guide rail (■). This movement allows the unit to rotate within the deflection plane around the center O of the surface to be scanned. This adjusts the inclination of the best image plane and the scanned plane. In this embodiment, the optical unit has a structure that rotates within the deflection plane with the center of the scanned surface as an axis, so the center of the best image plane and the center of the scanned surface are kept in the same state. The inclination with respect to the scanning plane can be adjusted. In addition, the guide rail I and mounting hole J on the base are fixed after adjustment using a standard optical unit, and the optical unit is adjusted using a standard base, so there is no possibility of failure. Unit replacement can be done easily.

A third embodiment of the optical deflection device of the present invention is shown in FIGS. 4(a) and 4(b). FIG. 4(a) shows the optical unit 1O with the lower side (
The attachment of the base 20, which is the main body of the apparatus, is a view seen from the front side), and FIG. 4(b) is a diagram showing the state in which the optical unit 10 is attached to the base 20. In the figure, on the optical unit side, there are a fixed positioning pin for determining the position in the lateral direction, and pins L and M for determining the position in the front-rear direction, and the pin M is movable in the front-rear direction.

On the base side, there are a guideline N that determines the position in the lateral direction and a guideline P that determines the position in the front and back direction. The pin K of the unit touches the guideline N, and the pins L and M touch the guideline P, so that the position of the unit is determined. By moving pin M back and forth, pin L
The unit rotates within the deflection plane around the axis, thereby adjusting the inclination of the best image plane and the scanned plane.

[Effects of the Invention] As explained above, according to the present invention, when the optical unit is attached to the base, the mounting position is adjusted so that the optical unit rotates, so that the best image plane and the scanned surface can be adjusted. Adjusted the tilt. Therefore, the processing accuracy and mounting of individual optical components can be made without making the accuracy extremely difficult, in other words, while avoiding a significant increase in cost, and maintaining sufficient stability over the entire scanning surface against environmental changes. We have achieved an optical deflection device that can obtain a spot diameter.

[Brief explanation of drawings]

FIGS. 1(a), (b), and (c) are views showing a first embodiment of the optical deflection device of the present invention, and FIG. 2(a). 3(b) is a diagram for explaining the adjustment of the inclination of the best image plane and the scanned surface; FIGS. 3(a) and 3(b) are diagrams showing a second embodiment of the optical deflection device of the present invention; FIGS. 4(a) and 4(b) are diagrams showing a third embodiment of the optical deflection device of the present invention. 1...Light source part 2...Rotating polygon mirror 3.4...F-θ lens 10...Optical unit 20...Base box 1 (shi) Mouth (C) Millet 20 (0)

Claims (2)

[Claims] (1) In an optical deflection device including an optical unit having a light source section and a deflector that deflects a light beam from the light source section, and a base to which the optical unit is attached, the optical unit rotates with respect to the base. A light deflection device, characterized in that the light deflection device is attached so that the light deflection device can be attached to the light deflection device. (2) Claim 1, wherein the optical unit is rotatably mounted within the deflection plane.
).